How many cells are there in the human body and how many microorganisms are there in a human body?

Which of the four major uses is predicted to change the least by 2020?

How do diseases caused by bacteria and diseases caused by viruses react to antibiotics?

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point